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Title: Measurement of diffusion coefficients important in modeling the absorption rate of carbon dioxide into aqueous N-methyldiethanolamine

Abstract

Natural gas processors use amine treating processes to remove the acid gases H{sub 2}S and CO{sub 2} from gas streams. Absorption rates of gaseous CO{sub 2} into aqueous N-methyldiethanolamine (MDEA) solutions were measured in a quiescent, inverted-tube diffusiometer by monitoring the rate of pressure drop. The absorption rate was found to be insensitive to the diffusion coefficient of CO{sub 2} in solution but very sensitive to the diffusion rate of bicarbonate and protonated MDEA ions. Evidence also suggested that chemical reaction equilibrium is rapid relative to diffusion. A numerical model was developed on the basis of these observations. The model was used to regress diffusion coefficients of bicarbonate and protonated amine, which must be equivalent by electroneutrality arguments, from measured absorption rates. Complete modeling of the absorption process also required data for the diffusion coefficient of MDEA in water. These were measured using a Taylor dispersion apparatus. CO{sub 2} absorption rates and diffusion coefficients of bicarbonate and protonated MDEA were obtained at 298.2 K and 318.2 K in solutions containing 20, 35, and 50 mass % MDEA in water.

Authors:
; ; ; ; ;  [1]
  1. Brigham Young Univ., Provo, UT (United States). Dept. of Chemical Engineering
Publication Date:
Sponsoring Org.:
Gas Research Inst., Chicago, IL (United States)
OSTI Identifier:
460726
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical and Engineering Data; Journal Volume: 42; Journal Issue: 2; Other Information: PBD: Mar-Apr 1997
Country of Publication:
United States
Language:
English
Subject:
03 NATURAL GAS; CARBON DIOXIDE; ABSORPTION; AMINES; SORPTIVE PROPERTIES; DIFFUSION; MATHEMATICAL MODELS; NATURAL GAS PROCESSING PLANTS; PROCESS SOLUTIONS; SOLUBILITY

Citation Formats

Rowley, R.L., Adams, M.E., Marshall, T.L., Oscarson, J.L., Wilding, W.V., and Anderson, D.J.. Measurement of diffusion coefficients important in modeling the absorption rate of carbon dioxide into aqueous N-methyldiethanolamine. United States: N. p., 1997. Web. doi:10.1021/je960254t.
Rowley, R.L., Adams, M.E., Marshall, T.L., Oscarson, J.L., Wilding, W.V., & Anderson, D.J.. Measurement of diffusion coefficients important in modeling the absorption rate of carbon dioxide into aqueous N-methyldiethanolamine. United States. doi:10.1021/je960254t.
Rowley, R.L., Adams, M.E., Marshall, T.L., Oscarson, J.L., Wilding, W.V., and Anderson, D.J.. Sat . "Measurement of diffusion coefficients important in modeling the absorption rate of carbon dioxide into aqueous N-methyldiethanolamine". United States. doi:10.1021/je960254t.
@article{osti_460726,
title = {Measurement of diffusion coefficients important in modeling the absorption rate of carbon dioxide into aqueous N-methyldiethanolamine},
author = {Rowley, R.L. and Adams, M.E. and Marshall, T.L. and Oscarson, J.L. and Wilding, W.V. and Anderson, D.J.},
abstractNote = {Natural gas processors use amine treating processes to remove the acid gases H{sub 2}S and CO{sub 2} from gas streams. Absorption rates of gaseous CO{sub 2} into aqueous N-methyldiethanolamine (MDEA) solutions were measured in a quiescent, inverted-tube diffusiometer by monitoring the rate of pressure drop. The absorption rate was found to be insensitive to the diffusion coefficient of CO{sub 2} in solution but very sensitive to the diffusion rate of bicarbonate and protonated MDEA ions. Evidence also suggested that chemical reaction equilibrium is rapid relative to diffusion. A numerical model was developed on the basis of these observations. The model was used to regress diffusion coefficients of bicarbonate and protonated amine, which must be equivalent by electroneutrality arguments, from measured absorption rates. Complete modeling of the absorption process also required data for the diffusion coefficient of MDEA in water. These were measured using a Taylor dispersion apparatus. CO{sub 2} absorption rates and diffusion coefficients of bicarbonate and protonated MDEA were obtained at 298.2 K and 318.2 K in solutions containing 20, 35, and 50 mass % MDEA in water.},
doi = {10.1021/je960254t},
journal = {Journal of Chemical and Engineering Data},
number = 2,
volume = 42,
place = {United States},
year = {Sat Mar 01 00:00:00 EST 1997},
month = {Sat Mar 01 00:00:00 EST 1997}
}